Approximately 34 million people are infected with human immunodeficiency type-1 (HIV-1) world-wide. More than two million new infections occur annually (1,2). These statistics could be reduced if at-risk individuals were provided antiretrovirl drugs for HIV pre-exposure prophylaxis (PrEP). We propose to develop a combination nano-microbicide containing cellulose acetate phthalate (CAP) as a HIV-1 entry inhibitor with dolutegravir (DTG), a HIV-1 integrase strand transfer inhibitor, for highly effective PrEP. Our preliminary data show that novel CAP-DTG combination nano-microbicide reduce cytotoxicity of DTG to cells. In vitro HIV prophylaxis using HIV indicator TZM-bl cells show that CAP-DTG combination nano-microbicide offers significantly higher protection from HIV-1 infection as compared to DTG solution and CAP nanoparticles indicating the importance of combination nano-microbicide. This proposal will extend our preliminary experiments and evaluate CAP-DTG nano-microbicide in thermosentive gel and DTG solution based conventional gel for cytotoxicity, intra-cellular delivery of DTG, in vitro HIV PrEP, and vaginal pharmacokinetics. In order to reach this goal, Specific Aim 1 focuses on development of DTG solution based conventional gel (DTG-gel), optimization and characterization of CAP-DTG combination nanomicrobicide for DTG loading, and incorporation of CAP-DTG combination nanomicrobicide into a thermosensitive gel (CAP-DTG-NPs-Gel) for vaginal delivery. Chemical stability of DTG in conventional gel and CAP-DTG-NPs-Gel will also be assessed.
Specific Aim 2 employs various cell lines and primary human cells to evaluate DTG-gel and CAP- NPs-DTG-Gel for cytotoxicity and intra-cellular delivery of DTG. The ability of DTG-gel and CAP-NPs-DTG-Gel to offer protection from HIV-1 infection will be tested in TZM-bl cells, PBMCs, and MDMs. We will evaluate vaginal pharmacokinetics of DTG-gel and CAP-DTG-NPs-Gel using female NOD SCID gamma (NSG) mice for up to 7 days. Drug dissemination will be determined using HPLC analysis to measure DTG levels in dissected tissue. We will evaluate tolerability of DTG-gel and CAP-DTG-NPs-Gel after repeated administration for 7 days by analyzing inflammatory cytokines in cervicovaginal fluid and immunohistochemical analysis of NSG tissue. As a laboratory within an undergraduate biology department with collaborators in attached professional schools, we are uniquely situated to expose undergraduates to state-of-the-art nanoparticle research. This project will incorporate education of undergraduate students in our investigation of the utility of combination CAP and DTG nano-microbicide in a thermosensitive gel delivery system as cost-effect, highly efficacious modality for HIV pre-exposure prophylaxis.
Innovation is needed to increase availability and efficacy of pre-exposure prophylactic anti-HIV-1 therapies. This proposal will develop cost-effective, novel, combination antiretroviral nanoparticles and examine their ability to inhibit HIV-1 infection and replication in human cellular model systems and dissemination in mouse model systems. Results from this proposal will show whether integrase inhibitor combination nanomicrobicide is potentially useful for human pre-exposure prophylaxis.
